In a heatproof bowl whisk together sugar, cornstarch, eggs,
five-spice powder, and a pinch salt until combined well. In a heavy
saucepan heat milk just to a boil and add in a slow stream to egg
mixture, whisking. Transfer custard to pan and bring to a boil over
moderate heat, whisking constantly. Boil custard gently, whisking, 1
minute. Remove pan from heat and cool custard, stirring
occasionally. Chill custard, covered. until cold, about 3 hours.

In a blender purée litchis with 1/2 cup cream and
stir into custard with remaining cup cream. Freeze custard in an
ice-cream maker. Ice cream may be made 1 week ahead.